The difficulty is that there is no absolute direct translation of agredecer into English, therefore we need to translate the feeling of the verb in each sentence where it is used. DL have one or two strange un-English sounding sentences, but it is a really good example of how it is not possible to translate a sentence word for word
Duo is having some trouble with the translation of agredecer into English. It accepts "The writers are thankful for their readers," but not "The writers are thankful to their readers." In BP is there is difference in how you say this two sentences? I'm guessing not if "for" is implied in BP. Seems like "to" should also be an accepted implication.
This kind of sentence does not need a preposition. You can say just "Eles agradecem os alunos", but also "Eles agradecem aos alunos". Both ways, though, are not the literal translation from English. If you use "be thankful" then it's "estar agradecido por / ficar grato por" (Estou agradecido por ter vindo me visitar)
It doesn't accept "The writers are thankful to their readers" because it is incorrect English. You are never thankful to someone or something, you are thankful for things/people and grateful to people. You also express thanks to people (because you express emotions to or at people/things), but you don't say you are "thankful to"
It'still not clear to me whether you have to use the "a" preposition with "agradecer" or not. The above sentence does not use it. But other part of the lesson do require it in the correct solution. So it this "a"preposition mandatory for indirect objects when those are placed after the verb ?
Não - but can we teach Duo to be more complete in accepting real English translations -- since there is no almost literal way to say this, and since it requires an Indirect Object in English with to, or for, or other options, can we stop debating the Portuguese and just correct the English answers to be inclusive?